• Appendix 9: Consultation response from Environment Agency 07/08/13

Proposal: The proposed construction of a barge house large enough to

house the barge, store equipment and provide display and

education opportunities including a replacement café ;

wetdock with a guillotine sluice gate to hold water at mean

high water so that the barge can be displayed to the public and

a dredged channel to enable access when river is at the

retained level of 1.7m AOD

• Location: Orleans Road, Twickenham, TW1 3BL.

Thank you for consulting us at the pre-application stage. We welcome proposals

which “make space for water” and restore more natural environmental processes

which can deliver multiple environmental, social and economic benefits.

Having reviewed the proposal we would like to highlight the following issues and

opportunities for this key riverside park. These are related to: Flood risk management,

Flood defences and climate change; and Biodiversity and fisheries

• Flood risk management

The site is located in the highest risk zone called Flood Zone 3 in front of the

Thames Tidal Defences. As such it could be considered to be functional flood

plain (FZ3b). The proposal is classified and water compatible (barge house) and

less vulnerable (cafe) in Table 2: Flood risk vulnerability classification of the

Technical Guidance to the National Planning Policy Framework.

Table 1: Flood zones sets out the suitability of certain type of development within

areas of flood risk. Water compatible development is classed as appropriate

development in flood zone 3B, however less vulnerably development is classified

as unsuitable at this location. In this case the less vulnerable element will be a

replacement café on a like for like footprint and so would not be

increasing/introducing new risk into the functional flood plain so we would have no

objection. In order for the proposal to be acceptable in its current form you should

discuss the issue of functional flood plain with Richmond Local Planning authority.

If the proposal were to progress to a planning application then you would need to

produce a Flood Risk Assessment (FRA). The FRA should be prepared in

accordance with the Technical Guidance to the NPPF. Much of the information

required to inform the assessment may be obtained from the London Borough of

Richmond‟s Strategic Flood Risk Assessment (SFRA), which shows local flood

risk at a strategic level.

Your FRA should include the following:

– Identification of the Flood Zone and vulnerability classification in accordance

with Table 2 of the Technical Guidance to the NPPF.

– Confirmation of the flood defences and standard of protection provided, to

confirm the level of residual risk in accordance with the SFRA for the borough.

– Estimation of flood depths at the site for a range of flood events, to calculate

internal flood depths in the event of a flood event.

– Suitable flood mitigation measures based on flood characteristics at site.

We recommend that you use flood resistance and resilience measures and

construction techniques to help reduce the impact of flooding should it occur.

Please refer to “Improving the Flood Performance of New Buildings: Flood

Resilient Construction” (CLG, 2007).

You may also wish to consider whether a Flood Warning and Evacuation Plan

would assist in reducing the impact of flooding on the future users of the

development. We do not normally comment on or approve the adequacy of flood

emergency procedures accompanying development proposals, as we do not

carry out these roles during a flood. Our involvement with this development during

an emergency will be limited to delivering flood warnings to occupants/users

covered by our flood warning network.

Paragraph 9 of the Technical Guidance to the NPPF states that those proposing

developments should take advice from the emergency services when producing

an evacuation plan for the development as part of the flood risk assessment. In all

circumstances where warning and emergency rs is fundamental to managing

flood risk, we advise local planning authorities to formally consider the emergency

planning and rescue implications of new development in making their decisions.

Our Customers and Engagement Team can provide any relevant flooding

information that we have available. Please be aware that there may be a charge

for this information. Please contact 01707 632 511 or email:

NETenquiries@environment-agency.gov.uk.

• Climate change and Thames Estuary 2100 (TE2100)

As the development is within the floodplain you will need to consider TE2100

advice. An assessment should be made on the implications that rising water

levels due to climate change would have on the development and how the flood

defences can be raised if required. We recommend discussing the proposed

works to the flood defences in this area with London Borough of Richmond upon

Thames and how it fits with the wider long term management of flood defence

structures in Richmond and Twickenham.

More information can be found at:

http://www.environment-agency.gov.uk/homeandleisure/floods/125045.aspx

• Flood defences

Its essential the level of flood defence protection is maintained for this area of

high risk and regular flooding at high tides. We have concerns on the potential

negative impacts of reinstating the subway from Orleans House Gallery to the

barge house. We recommend that an alternative form of access is considered or

we agree ways to maintain flood defences

Under the terms of the Water Resources Act 1991, and the Thames Land

Drainage Byelaws 1981, the prior consent of the Environment Agency is required

for any proposed works or structures, in, under, over or within 16 metres of the

landward edge of the tidal defence of the River Thames, designated a „main

river‟.

• Water Framework Directive

The Water Framework Directive (WFD) came into force in 2000 and is the most

substantial piece of EU water quality legislation to date. The Thames River Basin

Management Plan was produced in 2009 to provide an initial guide on how the

targets for water quality improvements as set out in the WFD could be met for this

catchement. All new activities in the water environment will need to take the

Directive and the river basin management plan into account.

A fundamental requirement of the Water Framework Directive is to attain good

ecological water quality status and that deterioration in the status of waters is

prevented. Any new development must ensure that these two fundamental

requirements of the Directive are not compromised.

As your development involves bank and in channel works you should investigate

if a WFD assessment is required. WFD assessments aim to determine the effects

of proposed schemes on ecological quality, identifying any potential impacts that

could cause deterioration in the status of a water body or could hinder the water

body from meeting its WFD objectives. More information can be found at

http://www.environment-agency.gov.uk/research/planning/125035.aspx

• Biodiversity and fisheries

Please refer to “Rivers by Design” which provides a useful guide for planners,

designers and developers, providing practical advice and information on restoring

and protecting rivers and sharing good practice case study examples of projects

that have been successfully implemented across Europe. This available from:

http://www.restorerivers.eu/ Due to the developments location and the potential for

work in the River Thames you should produce an environmental assessment to ensure

there is no risk to wildlife and look at ways to improve the riverside environment for people

and wildlife. We will also require a method statement setting detailing any in channel

works and how the impact on fish and aquatic biodiversity will be mitigated.

• Advice for developers

We have updated our advice for developers and it is now a joint agency

document with advice from Environment Agency, Natural England and Forestry

Commission, it‟s available to view on our website

http://www.environment-agency.gov.uk/business/sectors/136252.aspx

I trust hope our response is helpful and we look forward to working with you on

this exciting project. We are happy to review any draft reports prior to formal

submission. If you require any additional information please contact me . .

Yours sincerely

Sustainable Places – Planning Advisor

___________________________________________________________________

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